1. Field of the Invention
The present invention relates to the field of container handling apparatus and more particularly, to container handling apparatus utilizing one or more mechanically actuated grippers.
2. Prior Art
In container handling equipment such as bottle handling equipment, various types of grippers are used to hold, transport, uncase, etc., bottles and other types of containers. Some of this equipment utilizes mechanical grippers for container gripping purposes, as mechanical grippers tend to be simpler, more reliable and more readily designed into such equipment because of the lack of separate power requirements, pressure lines, vacuum lines, etc., characteristic of other types of grippers. Mechanical grippers generally are characterized as comprising some form of gripper assembly carried on a moving structure with each gripper having an actuating member appropriately disposed for either intercepting a stationary actuator member for the actuation thereof, or at least intercepting a member moving with respect thereto so that the force between the gripper assembly actuating member and the cooperatively disposed member is appropriate to actuate the gripper assembly as desired. Typically, the gripper assemblies are supported on one or more moving structures whereas the cooperatively disposed members for engaging the gripper actuating members are supported on a separate structure.
The preferred embodiment of the present invention is intended for use with the bottle handling apparatus of U.S. Pat. No. 3,975,260, which apparatus is representive of the types of apparatus with which the present invention would be utilized. That patent discloses what is more commonly referred to as an electronic bottle inspector wherein bottles delivered on an inlet conveyor are engaged by mechanical grippers mounted on a starwheel assembly and carried past an inspection head which analyzes the image of the bottom of the bottle to determine whether the bottle contains foreign matter. If the bottle does not contain foreign matter, the respective gripper is released at a first position in the starwheel assembly rotation so as to be picked up by an outlet conveyor, whereas if the bottle does contain contamination or is otherwise rejected, the bottle is released at a second position in the starwheel rotation so that the rejected bottles may accumulate on a reject table or be delivered to a reject conveyor. Obviously from this description, each mechanical gripper must be actuated to receive a bottle at the pickup point, with most of the grippers being opened to release the bottles at the outlet conveyor, as the percentage of bottles which are reJected in the normal course is relatively low.
In the apparatus of U.S. Pat. No. 3,975,260, the starwheel assembly is supported on a vertical shaft, bearing mounted in a lower housing or chassis, with the inspection head being separately mounted on the chassis so as to be stationarily and cooperatively disposed with respect to the starwheel assembly for inspecting bottles carried by the starwheel thereby. The gripper assemblies are closed at the bottle pickup point by a cam mounted to the inspection head structure, with the grippers being opened by another cooperatively disposed cam, also mounted to the inspection head assembly. At low to moderate operating speeds, the system operates very smoothly, and even at high speed functions properly and without difficulty. However, at the higher speeds, the system does not operate as quietly as one might desire, and vibration may be encountered as a result of the inspection head assembly and/or starwheel assembly vibrating on their less than perfectly rigid support structure. The problem, of course, is not made any easier by the fact that this type of equipment generally must operate at a speed determined by the rest of the system in which it is used rather than at a speed to be determined by the manufacturer of the electronic bottle inspector itself and at certain speeds the repetitive cam force may tend to excite one or more resonances in the system to generate the distracting noise and vibration.